Flexible Mn-decorated NiCo2S4 core–shell nanowire arrays for a high performance hybrid supercapacitor electrode with a long cycle life

Abstract

In this work, 0.5Mn–NiCo₂S₄ core–shell nanowire arrays are rationally designed and directly employed as binder-free electrode materials for supercapacitors. The as-fabricated product exhibits a high areal capacity of 3.13 C cm⁻² at a current density of 2 mA cm⁻² and an excellent stability with 78.59% capacity retention after 6000 cycles. An asymmetric hybrid supercapacitor, assembled by utilizing 0.5Mn–NiCo₂S₄ core–shell nanowires as the positive electrode and activated carbon as the negative electrode, achieves a relatively high volumetric energy density of 8.80 mW h cm⁻³ at a volumetric power density of 220.103 mW cm⁻³ and a high retention of 2.29 mW h cm⁻³ at a power density of 704.51 mW cm⁻³. Besides, the asymmetric device shows remarkable cycling stability with 83.93% capacity retention after 6000 cycles.